Security for webserver behind router?

[Jay O'Brien]

I've brought up a 5.3 Release machine as a learning tool, 
with apache 1.3. It is on a LAN with Windows machines, and 
port 80 (and only port 80) is open and directed by the 
Linksys router to the FreeBSD machine. It is working fine so 
far, but my learning curve is slower than I would like. 

I know that there's lots to learn and do later about 
security, when I bypass the Router and use the FreeBSD box 
as the NAT device, but for now I would like to confine my 
learning to Apache, with only port 80 open. I do have ftp 
and ssh enabled on the LAN for access by the Windows boxes.

As I haven't done anything for security on the FreeBSD 
machine, am I exposed to anything by having port 80 open? Is 
there anything I should do now? 

Jay O'Brien
Rio Linda, California USA